Conventional wheelchairs typically comprise a non-reclining seat made of a flexible material such as vinyl, canvas or the like stretched across a frame which is supported between two large drive wheels and two small front swivel casters. Normally, conventional wheelchairs may be made to fold or collapse by drawing the sides of the wheelchair's frame together, thereby reducing its width. This allows the wheelchair to be more easily handled and stored.
Many elderly or handicapped persons spend a large part of each day in a wheelchair. However, conventional folding wheelchairs are not well suited for such extended use and may adversely affect the health of these persons. For example, elderly persons may develop sores or flexion contractures of the hips and knees because they are physically unable to shift their weight in the wheelchair. Similarly, kyphosis, an abnormal curvature of the spine which commonly afflicts the elderly, may be aggravated by sitting upright for long periods of time. Persons suffering this condition may thus be forced to remain in bed for a greater portion of the day, adversely affecting their quality of life.
To address these problems, wheelchairs having seats with reclining backrests were developed. These wheelchairs allow a user to shift his or her weight by reclining the seat back to decrease pressure on bony prominences and reduce the likelihood of developing sores and muscle aches and spasms. Reclining wheelchairs may also position a kyphosis afflicted user so that gravity may help reverse or retard his or her condition. Further, reclining wheelchairs may provide an improved feeding position for severe kyphosis sufferers, who, when sitting in a conventional chair or wheelchair, would be essentially face down.
For some persons, especially the elderly, independent movement of the seat bottom and seat back may be undesirable because such movement may result in skin shear of an elderly user's back and buttocks. Consequently, it is desirable to provide a tilting seat having a seat bottom and seat back which may be tilted simultaneously at a fixed angle to each other.
The center of gravity of a conventional wheelchair typically lies somewhere forward of an imaginary line extending between its large drive wheels. This positioning of the center of gravity makes the wheelchair extremely stable. However, for a wheelchair having a reclining or tilting seat, the center of gravity of the wheelchair and its user may shift rearward as the seat is reclined or tilted. Consequently, there exists a danger that the wheelchair may tip over and possibly injure is user. To solve this problem, a wheelchair may include a mechanism which allows the seat to be slid forward on a slide, track or the like after it is reclined or tilted to restore the center of gravity to a stable location. However, such mechanisms tend to be extremely complex since they must both tilt or recline the seat and slide the seat forward in the wheelchair frame. Because of this complexity, these mechanisms may also be costly, unreliable and, especially if they are unpowered, difficult, if not impossible, for an elderly user to operate. Further, such mechanisms may be unable to simultaneously recline the seat and slide the seat forward creating a window of time where the wheelchair is susceptible to tipping.
Wheelchairs also typically include leg supports or rests adapted to support a user's legs and feet. Many times, however, a person who is physically unable to stand may have sufficient mobility and strength in his or her legs to still be able to use his or her legs and feet to propel the wheelchair. For these persons, leg supports may make such locomotion difficult if not impossible. However, the same individual, when desiring to rest or remain immobile, may desire leg supports to sit comfortably within the wheelchair.
For these reasons, it would be advantageous to provide a wheelchair having a tilting seat adapted to tilt without upsetting the wheelchair's center of gravity wherein the seat includes a seat back adapted to recline independently of the seat bottom. It would also be advantageous to provide a wheelchair having leg supports adapted to be easily retracted beneath the seat when not in use.